WP Details:F1.7.4 (Steel Deck - Substrate Overlay Board)

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WP Details:F1.7.4 (Steel Deck - Substrate Overlay Board)

Division D - Construction Details

WP Details:F1.7.4 (Steel Deck - Substrate Overlay Board)

Notice to Reader
Images used in a Construction Detail are representative and not prescriptive. Nor are they necessarily drawn to scale. Rather, they are provided to visually convey the requirements of the Standard they represent. Unless otherwise required by the Standard, dimensions, the selection of materials and their application remains the responsibility of the Design Authority.

The full text of the referenced requirements in the Standard may be read by using the blue hyperlinks
Waterproofing Details for Plazas, Promenades and Terraces



(1) Deck Overlay Substrate Boards
two layers of fibre-mat reinforced cement board, minimum thickness 9.5 mm (3/8"), conforming to ASTM C1325-04 or gypsum board with fibreglass facer and silicone treated core, minimum thickness 12 mm (1/2"), conforming to ASTM E 661
(2) Primary Waterproofing Membrane
Fully adhered to acceptable substrates.
(3) Membrane Primer or Adhesive
Proprietary primer or adhesive, application and quantities as directed by membrane manufacturers published application specifications.
(4) Membrane flashing (stripping)
Carried up wall minimum 200 mm (8") above deck surface a minimum of 100mm (4") above top surface of waterproofing assembly. Typical low outside parapet wall depicted, membrane carried over top of wall and down exterior face minimum of 50mm (2").
(5) Insulation
Optional: Extruded, Expanded Polystyrene, Type 4, CAN/ULC-S701-97, compressive strength of 240 kpa (35 psi).
(6) Metal Base Flashing
Required on all waterproofing assemblies. Flashing lengths joined by use of S-locks or standing seam joints.
(7) Metal Cap Flashing
Must overlap exterior wall finish. See 15.1 for RoofStar Guarantee Standards applicable to base metal flashing. Fasten with continuous concealed clip-type fasteners or cladding screws evenly spaced between seams. See 16.3 Attachment.
(8) Drainage Medium
Proprietary (purpose-made) drainage board designed to provide secondary drainage below poured concrete wearing slabs and unit masonry (pavers, brick or stone) set in mortar beds.


(A) Acceptable Deck
Steel deck depicted.
(B) Wall Finish
Concrete depicted.

NOTE: See the Standard for additional requirements.

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